1. Field of the Invention
This invention relates to borehole televiewer signals, or rotary scan signals, whether produced by a single sub-surface rotating transducer or from a plurality of rotating transducers. It provides a system for on-line processing of the borehole scan signals so that for each rotation of the transducer producing a selected number of separate sonic scan signals, each of which is customarily recorded as a horizontal line, or as an elliptical line, with successive repetitions of the sonic scan signal being placed beside the previous one so as to form a plurality of line traces or "helical traces" on a page. These are normally recorded on a cathode ray tube type recorder.
More particularly, it concerns the on-line processing of signals at the surface, so that a variety of signal enhancement processes can be applied to the incoming signals in order to make them more noise-free, or to better illustrate the geology of the walls of the borehole.
2. Description of the Prior Art
Examples of the prior art are illustrated by U.S. Pat. Nos. 3,369,626, entitled: "METHOD OF AND APPARATUS FOR PRODUCING A VISUAL RECORD OF PHYSICAL CONDITIONS OF MATERIALS TRAVERSED BY A BOREHOLE", issued Feb. 20, 1968 in the name of J. Zemanek, Jr.; 3,668,619, entitled: "THREE-DIMENSIONAL PRESENTATION OF BOREHOLE LOGGING DATA", patented June 6, 1972 in the name of Charles L. Dennis; 3,550,075 entitled: "SYSTEM FOR DISPLAYING TIME INFORMATION IN ACOUSTIC WELL LOGGING SYSTEM", issued Dec. 22, 1970 to D.W. Hilchie et al; and 3,835,953 entitled: "ACOUSTIC CALIPER LOGGING", issued Sept. 17, 1974 to Jerald C. Summers. There is also additional art recorded in the form of other patents, and in technical papers presented at technical society meetings, so that further description or statement of the art is not necessary at this time.
The prior art has provided only a very simple presentation of the circular scans of the transducer in the borehole, such as the amplitude of the reflected sonic pulse as a function of angle of rotation of the sonic transducer. Another presentation would be the time of travel of the sonic pulse out from the transducer and back to the transducer from a reflecting surface. In the former presentation, each individual amplitude at one angle of rotation represents one pixel of the display. Separately, the caliper has been displayed in a way such as illustrated in the Summers patent.